1. Field of the Invention
This invention relates to fuel injection intake manifold systems. In particular, this invention relates to a manifold system having reduced external dimensions in which sequentially firing cylinders are supplied with sufficient, uniform air flow for uniform and high power output.
2. Description of the Prior Art
The present invention relates to an improvement in the intake manifold structure for a V-Type internal combustion engine or other forms of internal combustion engines. A typical V-Type internal combustion engine has two banks of cylinders, one on the left and one on the right. Typically, to make the engine compact, an intake manifold for distributing air among the respective cylinders is interposed between the left and right cylinder banks. Engine performance can be improved by using the inertia of the intake air entering the engine and minimizing resistance to flow of such intake air. This can be done with an intake manifold with air passages of sufficient lengths and effective areas to optimize the performance of the engine. As engines have decreased in size due to space and weight considerations, difficulties have arisen in maintaining the requisite lengths and effective areas to optimize the engine's performance.
Additionally, fuel injected V-8 engines characteristically fire cylinders sequentially. No matter which firing order is chosen, at least one, and possibly two pairs of adjacent cylinders will always fire sequentially. These sequentially firing cylinders demand air sequentially. A problem exists in providing air to these adjacent sequentially firing cylinders. These cylinders compete for the air supply and "starve" each other. This causes non-uniform flow to the cylinders resulting in non-uniform power output.
Still further, it has been found that having demand runners, or tubes, such as ram pipes, which draw air from a common plenum chamber with a throttled supply, is more beneficial than throttling each demand runner. However, since some cylinders in the engine have intake strokes that overlap the intake strokes of other cylinders, if all of the cylinders are drawing from a common plenum chamber, the charging of one cylinder will interfere with the charging of another cylinder, thereby decreasing the volumetric efficiency and preventing uniform charging. To solve this problem, various types of manifold systems were developed. Such systems however did not resolve or even alleviate the problem.
Additionally, with the decreasing size of automobiles, lower hood line designs and lower frontal areas, there is a need for a compact fuel injection manifold having a low hood profile. Many known fuel injection manifolds, to achieve such low hood profile limitations, have serviceability problems, i.e., parts are difficult to replace. In particular, to make repairs on the engine, the intake manifold must be removed to obtain access to, for example, the valve covers or to remove the fuel injectors. For example, the standard Ford manifold prevents removal of the valve cover and the injectors. Further, the valve cover cannot be removed until the throttle body and EGR valve is removed. To achieve such low profiles, the manifolds and plenums must have sharp turns and curves to provide sufficient length. Such a configuration causes higher pressure drops and decreased flows when compared to higher profile manifolds with gentler turns and curves.
Still further, it is known, for example, that it is an advantage to have tapered air demand tubes connected to the cylinders. This allows for higher and more uniform air flows through the engine. It is also advantageous for today's high RPM engines to have long, i.e., about eighteen inches long, demand runners to the cylinders. Providing such configurations with known manifold systems without having sharp bends is almost impossible and snaking them back and forth across the engine causes high pressure drops and low flows.
Other modifications can be made to manifolds which will enhance the performance of engines. So, for example, it is found that being able to vary the length of the path of flow of air from the inlet of the engine to the cylinder will affect the performance of the engine. There is a long history of tuning inlet manifolds to achieve maximum engine performance. A problem with such a tuning arrangement often is that the tuning is designed for a particular spot on the performance envelope of the engine or a specific performance configuration of engine rpm. It is desirable to be able to adjust the manifold configuration to optimize or improve performance of the engine at more than one particular point and over as large a range as possible. Alternatively, it would be desirable to have the manifold adjustable for operations at the high end or high rpm operation of the engine and also at the low end or low rpm operation of the engine.
Possibly relevant U.S. Patents in this area of technology are:
U.S. Pat. No. 2,916,027 to Chayne et al. PA1 U.S. Pat. No. 2,947,294 to Bird et al. PA1 U.S. Pat. No. 4,577,596 to Senga PA1 U.S. Pat. No. 4,741,295 to Hosoya et al. PA1 U.S. Pat. No. 4,930,468 to Stockhausen PA1 U.S. Pat. No. 4,957,071 to Matsuo et al. PA1 U.S. Pat. No. 4,962,735 to Andreas PA1 U.S. Pat. No. 5,000,129 to Fukada et al. PA1 U.S. Pat. No. 5,005,536 to Suzuki et al. PA1 U.S. Pat. No. 5,063,885 to Yoshioka PA1 a! a first elongated secondary manifold disposed substantially parallel to and above the first bank of cylinders; PA1 b! a second elongated secondary manifold disposed substantially parallel to and above the second bank of cylinders; PA1 c! a first set of a plurality of substantially parallel, spaced apart, demand runners joined to the first secondary manifold along its length, each demand runner extending from the first secondary manifold to a cylinder in the second bank of cylinders and in fluid connection with the first secondary manifold and the cylinder; PA1 d! a second set of a plurality of substantially parallel, spaced apart, demand runners joined to the second secondary manifold along its length, each demand runner extending from the second secondary manifold to a cylinder in the first bank of cylinders and in fluid connection with the second secondary manifold and the cylinder; PA1 e! a first set of a plurality of substantially parallel, spaced apart, supply runners joined to the first secondary manifold along its length and in fluid connection therewith; and PA1 f! a second set of a plurality of substantially parallel, spaced apart, supply runners -joined to the second secondary manifold along its length and in fluid connection therewith.
U.S. Pat. No. 2,916,027 to Chayne et al. describes an induction system for an internal combustion engine. The system includes longitudinal arms disposed above and parallel to the cylinder blocks. A plurality of Substantially identical ram pipes interconnect the arms to the cylinders for supplying a charge thereto. The ram pipes lead from the arm to the opposing bank of cylinders. A filtering device is provided in the central plenum to aid in silencing the acoustic noise developed in a resonant tuned system. There is no teaching or suggestion of balancing the flow between the various ram pipes, other than by adjustment of the volume of the arms (49, 50 of FIG. 2, thereof) from which the ram pipes extend, and adjustment of the volume of the header duct (46 of of FIG. 2, thereof).
U.S. Pat. No. 2,947,294 to Bird et al. describes an intake manifold for an internal combustion engine in which the ram pipes are arranged in groups of cylinders (e.g., one group of cylinders 1,4,6 and 7 and another group of cylinders 2,3,5 and 8), with the cylinders in a common group having the least amount of overlapping of the intake strokes. By a careful selection of the cylinders that comprise each group, there is a minimum amount of overlapping of the charging cycle or the intake strokes of the cylinders charged through a common chamber.
U.S. Pat. No. 4,577,596 to Senga describes an intake manifold for a V-Type internal combustion engine with supply tubes in the shape of a horseshoe. Branch tubes are integrally formed with the supply runner to provide communication between the supply runner and the cylinder intake port. Fuel injection nozzle mounting holes are formed in the branch tubes at a point just above each cylinder intake port. This design does not address the issue of adjacent drawing cylinders overlapping on the charging cycle and the problems associated therewith.
U.S. Pat. No. 4,741,295 to Hosoya et al. describes an intake manifold system for a V-Type multiple cylinder engine that can be accommodated within a gap defined between the two cylinder banks of the engine in a highly compact manner. The system does not address the issue of adjacent drawing cylinders overlapping on the charging cycle and the problems associated therewith.
U.S. Pat. No. 4,930,468 to Stockhousen describes an induction system for a multi-cylinder internal combustion engine. This reference does not teach an intake manifold system or address the issue of adjacent drawing cylinders overlapping on the charging cycle and the problems associated therewith.
U.S. Pat. No. 4,957,071 to Matsuo et al. describes an intake system for a V-Type internal combustion engine having two banks of cylinders. The intake system is comprised of two subcollectors disposed above the respective two banks of cylinders and connected with the cylinders in the banks. The main collector is disposed above, and between, the two banks of cylinders and is connected through a throttle with the two sub-collectors. Generally, the system is a cross ram design with a central supply plenum with a single split balance tube connecting the two runner supply plenums. The system does not address the issue of adjacent drawing cylinders overlapping on the charging cycle and the problems associated therewith. Further, the system overhangs both the front and rear of the engine and the valve covers, poorly uses engine compartment space and has poor serviceability.
U.S. Pat. No. 4,962,735 to Andreas describes an intake system for multi-cylinder internal combustion engines. The system has suction pipes that extend in a longitudinal direction and are connected to the intake channel leading toward the intake valve by means of passages of different lengths. The system uses a dual supply plenum. A control element is provided for selectively activating one of the two flow paths. The design is essentially another approach to variable inlet tuning, such as in U.S. Pat. No. 4,930,468 to Stockhousen. Due to the complexity of the system, a great deal of under hood space is utilized and serviceability is poor. This system does not address the issue of adjacent drawing cylinders overlapping on the charging cycle and the problems associated therewith.
U.S. Pat. No. 5,000,129 to Fukada et al. describes an intake system for a V-Type engine having a plurality of cylinders disposed in each of left and right-hand cylinder banks with a central surge tank disposed above the space between the left and right cylinder banks. Left and right surge tanks are respectively disposed above the left and right cylinder banks. Communicating passages connect the central surge tank with the left and right surge tanks, and discrete intake passages connect the left and right surge tanks with the cylinder. At least one of the communicating passages on each side of the central surge tank is disposed between the discrete intake passages on the side of the central surge tank. This system provides an intake system in which the effective volume of the surge tank can be increased without substantially increasing the overall size of the engine. This system does not address the issue of adjacent drawing cylinders overlapping on the charging cycle and the problems associated therewith.
U.S. Pat. No. 5,005,536 to Suzuki et al. describes two embodiments of compact high performance induction systems for V-Type engines that include pairs of plenum chambers that extend over the respective cylinder banks. First pairs of runners extend from an inlet opening in each plenum chamber to an outlet opening that communicates with the cylinder of the opposite bank. Second pairs of intake passages are provided which extend from inlet openings in the respective plenum chambers to outlet openings in the cylinders of the adjacent cylinder head. The first intake passages have portions that extend through the other plenum chambers and the second intake passages communicate with the cylinders through these intermediate portions. The intermediate portions are curved and in one embodiment the second intake passages are tangential to these curved portions and in the other embodiment they are radial to it. Each cylinder of the engine is thus served by both long low speed runners and short high speed runners. This system does not address the issue of adjacent drawing cylinders overlapping on the charging cycle and the problems associated therewith.
U.S. Pat. No. 5,063,885 to Yoshioka describes an improved high efficiency compact induction system for a V-Type internal combustion engine. The system includes a plenum chamber that extends through the center of the engine and a plurality of intake pipes that extend from the intake ports of the cylinders of one of the banks, across the center that enter the plenum chamber adjacent the intake ports of the other cylinders across the center and enter the plenum chamber on the side adjacent the intake ports of the one cylinder bank. The points of entry of the intake pipes with the plenum chamber lie under the other intake pipes to provide adequate length for the intake pipes and maintain a short overall length for the induction system. This system permits packaging long inlet runners by using the space in the center of the banks of cylinders. There would be significant problems in using this system in a push rod engine as the cam and push rods use considerable space in such area. This system does not address the issue of adjacent drawing cylinders overlapping on the charging cycle and the problems associated therewith.
The above known systems, to various degrees, provide very poor serviceability, are extremely complex designs and do not address the problem of adjacent demanding cylinders. Further, they allow relatively little space or latitude for demand runner taper. Runner taper greatly enhances cylinder filling, volumetric efficiency, and power output.